Elimination of Odors Emitted from Hot-Melting of Recycle PS by Oxidative-Reductive Scrubbing

Hot-melt granulation of waste plastics emits fumes with unpleasant plastic-burning odor during the heating process. This study uses sodium hypochlorite (NaOCl) solution to scrub and oxidize the volatile organic compounds (VOCs) and the associated odors from polystyrene (PS) hot-melting exhaust. An alkaline hydrogen peroxide (H2O2) solution was followed to remove Cl2 emitted from the oxidative solution. Laboratory scrubbing bottles with a liquid volume of 600 mL were used with the hot melt gas injected into the system at a rate of 1 L/min at 25°C.Results indicate that by purging the test gas through a solution with an available chlorine of 300-370 mg/L at an adjusted pH (6.5-7.0) for oxidation of the absorbed odorous compounds, and then through a solution with pH ＞ 12.0 and 0.35% H2O2 for absorption and reduction of Cl2 (＜ 11.2 ppm) in the exhaust gas from the oxidation liquid, around 90% of the VOCs in the range of 3.2-55.5 ppm (expressed as methane equivalent) was removed.Estimations indicate that it requires around 1.62, 0.0452, and 0.0827 kg NaOCl solution (12% available Cl2), H2O2 solution (35% H2O2), and sodium hydroxide solution (45% NaOH), respectively, for scrubbing 1,000 m^3 of the exhaust gas with 10 ppm NMHC (expressed as methane equivalent). The chemicals cost a total of approximately USD 0.32.The study has developed a new, effective and economic process for reducing odorous compounds in the hot-melted gas. When commercialized the process is hoped to decrease a lot of odorous complaints.

並列關鍵字

Renewable polystyrene ； Hot melt ； Sodium hypochlorite ； Hydrogen peroxide ； Odor control

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